Aircraft



L- BREGUET.

AIRCRAFT.

APPLICATION FILED .IAN- 25| I92I. 1 ,429,484. v Patented Sept. 19, 1922.

2 SHEETS-SHEET 2.

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Patented Sept. 19, 1922.

Urrea are LOUIS BREGUET, 0F vEIfIZY-VILLACOUBLAY, FRANCE, AssIG'NoR To, SOCIT ANONYME DES ATELIERS nAvIATIoN LoUIsBREG'UET, oE-rAnIs, FRANCE.

AIIcRArT,

To all vwhom 'it' may concern: l

Be it known that I, LOUIS BREGUET, a citizen of the Republic of France, residing in Velizy-Villacoublay (Seine-et-Oise) ,France, have invented new and useful Improvements in Aircraft, which is fully set forth in the following specification. v

This invention has for its principal object to provide aircraft with stream-line tubular struts presenting lessened and equal resist-` p .the said tubes being mounted in U-shaped ance to bending in every direction. y. p

In the construction of aircraft, round tubes are generally employed to intertie upper and lower longitudinale.

According to the present invention thev resistance to the wind which is presented by a circular cross-section is considerably reduced by the employment of tubes of stream-line.

section. As a set-olf to such a section, the moments of inertia in relation to thetwo principal axes are unequal. In determining the resistance to bending the minimum moment of inertia must be taken into account. Therefore the stream-line tubes, for a given end thrust load, have a section and weight greater than would be the case with an ordinary tube giving the same resistance to bending in every direction.

It is for the purpose of ensuring equal resistance to bending that the struts according to the present invention have been constructed, the said struts being each composed of, or comprising, two curved tubes of stream-line form in transverse section, their ends being fitted and secured in U-shaped connecting, or elbow, pieces and they being reinforced by cross-braces.

The following description, with reference to the accompanying drawing, gives an eX- ample which will enable the manner in which the invention can be carried out to be fully understood.

Figure 1 is a transverse section of a stream-line tube.

Figure 2 is an elevation of a strut made in accordance with one way, and Figure 3 is an elevation .of a strut made in accordance with another way, of carrying out this invention.

Figure 4 isan` elevation, in a plane, at right angles to that of Figures 2 and 8.

Figure 5 is a detail (drawn to a larger scale) showing an arrangement for connecting the struts with the longitudinals.

The two principal moments of inertia of a tube of a section such as that shown in Figure .1, are taken in relation to the two axes @,X, and @,Y, and,'in determining the resistance to bending, thewminimum moment of inertia in relation .tov @,Y, must be taken intoaccou-nt. l y l u vIn order to obtain equal resistance to bending in ,every direction, each strutis madel with two curved tubes V and .V-l. of streamline form in transverse section, the ends of connecting, or,elbow-, pieces N. lfllubesform-l ing, or riveting, zwanen, En, a uma ythe ensure the same resistance to bending in the two directions @,X, and 0,Y. Y f

The system ofconnecting the struts with the 'longitudinale maybe ofthe ball-andsoclret type, and mayconsist, flor example, of.l a partially spherical piece R (Figure 5)'-in one with the lower and upper elbow-pieces N, and arranged in a socket-piece S, riveted to the corresponding longitudinal andA secured in position by a screw-cap S1.

In orderl to lessen the strain tending to bring the cross-stays A,B; C,D; and E,F, out of the straight in relation to the stream-line tubes, the places at which the said cross-stays are attached to the stream-line tubes V,V1, are furnished with cross-braces A,D; B,C;

.C,F; and D,E, as indicated in Figure 3.

In order to ensure good resistance in the perpendicular plane, other diagonal crossfree lengths exposed to bending stresses in the `direction of the arrow L, are reduced about one half, by the tubes T and To, which, with the absorption of but little force, keep the middles of the struts V and V0 supported, and transmit the strain to the transverse pieces thus constituting a practically rigid whole.

The described construction furnishes stream-line struts of equa-l resistance to bending in every direction, the unsupported length being about half that which is the case in ordinary strutsl The tubes T, To, being of smal-l section the weight of the whole strut is considerably reduced which is the intention and effect oft the diagonal bracing.

It is of course understood that the details of the arrangements hereinbeore described are only examples and that the invention is not limited to thet precise details hereinbefore described and illustrated, as they may be varied without departing from the nature of this invention.

Having now particularly described and ascertained the nature ofy this invention, andin what man-ner the same is. to be performed7 declare that what I claim is:

l. An aircraft strut comprising two tubes of curved shape; having their concave portions oppositelyl situated, means 'for connecting together the ends o'f the said tubes, means yfor cross-connecting the two tubes,

and means 'for securing the said strut toi the,

longitudinals.

2. An aircraft strut comprising two tubes of curved shape having their concave portions oppositely situated and of stream line necting the two tubes, and means for securing the said strut to the longitudinals.

3. An aircraft st-rut comprising two tubesl 'of curved shape having their concave portions oppositely situated;` and of stream line cross-section, double-branched tubeshaped connecting members for attaching the ends of the said tubes together, crosspieces whose ends are secured to the two tubes' for cross-connecting the said strut, together with bracing wires for connecting the said cross-pieces, and a ball-and-socket joint i'ior connecting the said strut to each of the longitud'inals.v

at. rfhe combination in an aircraft, of a front strut and a rearl strut each comprising two tubes of curved shape having theiil concave portions cppositely situated, and oln` stream line cross-section, double-branched tube-shaped connecting members for attaching the ends of said tubes together, cross'- pieces whose ends are secured to the two tubes'for cross-connecting the strut, together with bracing wires for connecting the said cross-pieces, ball-'and-socket joints for connecting said struts to theV longitudinals ci.

the air-craft, and a cross-bar connecting the forward strut with the corresponding rear strut.

In testimony whereof l have signed thi specification,

LC UIS BREGUET. 

